Insulation



March 14-, 1939. c G, MUNTERS I 2,150,182

INSULATION v Filed March 12, 1936 3 Sheets-Sheet 1 March 14, 1939. c. e. MUNTERS 2,150,132

INSULATION Filed March 12, 1936 3 Sheets-Shee t 2 v M/f INVE%OR.

4 ATTORNEY.

March 14, 1939. c G MUNTERS 2,150,182

INSULATION Filed March 12, 1936 3 Sheets-Sheet 3 av ENTER. BY W AATTORNEY.

Patented Mar. 14, 1939 UNITED STATES PATENT OFFICE 2,150,1s2 INSULATION Application March 12, 1936, Serial No. 68,391

In Sweden March 13, 1935 3 Claims.

My invention relates to heat insulation and particularly to such insulation for use in connection with refrigerator cabinets or other containers in which itis desired to maintain a low temper-ature.

The chief object of my invention is to prevent the condensation of moisture within the insulation, and to assure the rapid evaporation of any moisture which may be formed in the insulation. A further object of my invention is to remove water vapor from the air within the insulation. Further objects and advantages of my invention will be apparent from the following description considered in connection with the accompanying drawings forming part of this specification and of which: I

Fig. 1 is a cross-sectional View of a refrigerator cabinet including one embodiment of my invention and is taken on the line I-l of Fig. 2;

Fig. 2 is a cross-sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a cross-sectional view similar to Fig. 2 but showing a different embodiment of my invention;

Fig. 4 is a cross-sectional view taken on the line 44 of Fig. 3;

Fig. 5 is a view on an enlarged scale of an element shown in Figs. 3 and 4;

Fig. 6 is a view partially in cross-section showing a modification of a part of the device shown in Figs. 3 and 4 Fig. 7 is a cross-sectional view taken on the line 'I-'I of Fig. 6;

Fig. 8 is a cross-sectional view of a still further 35 embodiment of my invention and is taken on the line 8-8 of Fig. 9; K

Fig. 9 is a cross-sectional view taken on the line 99 of Fig. 8; r

Fig. 10 is a cross-sectional view taken on the 40 line III-I of Fig. 8;

Fig. 11 is a perspective view of a portion of the device shown in Figs. 8 and 9; and

Fig. 12 is a cross-sectional view of a still further embodiment of my invention.

Referring more particularly to Figs. 1' and 2 reference character Ill designates generally arefrigerator cabinet including a food storage space I I adapted to be cooled by an evaporator or other cooling unit I2. Access to space II is had by 50 means of a door I3.

4 That portion of the cabinet II) which encloses the space II includes an outer shell I4 and an inner shell I5, preferably made of sheet metal and secured to a framework I6. In the space between shells I4 and I there is disposed in spaced relation a plurality of layers of insulating material I'I. As shown, insulation I'I consists of so-called double bottom corrugated cardboard, in other words, a corrugated piece of cardboard disposed between two 'flat'sheets of cardboard. Preferably, lustrous metal foil, such as aluminium, is applied to the outer sides of both of the flat sheets. Layers I'I constitute intermediate shells and are supported from the framework I6, the shells having sufficient rigidity so that no further support is required.

Outer shell I4 is substantially air-tight, but in practice it is impossible to effect a perfect seal between the shell and the framework I6 and the wall section I8 which supports evaporator I2. Consequently it is impossible to absolutely prevent the leakage of warm air into the space between the -shells I4 and I5. Inasmuch as this air always contains a certain amount of "moisture, there is a tendency for this moisture to condense due to the reduction in temperature of the air caused by the reduced temperature existing within the space I I. In order to prevent this condensation, inner shell I5 is formed with one or more openings I9 adjacent the lower part of the shell which establishes communication between the space II and the space formed between shell I5 and the innermost layer of insulation IT. The

layers II, or some of them, are formed with open-v ings 20 in their lower parts which establish communication between the spaces defined by the layers. In the embodiment shown, all except the outermost layer H are formed. with openings 20. At the top, the layers I! are formed with openings 23, while inner shell I5 is formed with an opening 24.

The support I2 constitutes a heat exchanger which forms a part of an absorption refrigeration system and is connected to the evaporator I2 and to other parts of the system indicated diagrammatically, at A. The refrigeration system is adapted to be operated by heat, as by a burner B, for example. The refrigeration system including the portion diagrammatically indicated at A, heat exchanger I2 and evaporator I2 may be of a type well-known in the art and like that generally within food compartment I I is chilled by contact with evaporator I2 and flows downwardly through During the operation of the refrigerator, air

the space due to an increase in its specific gravity. A part of this chilled air passes through openings I9 and displaces warm air upwardly in the direction of arrows 25, which air flows into the food space II through opening 24. A part of the chilled air which is passed through openings I9 passes downwardly in the direction of the arrows 26 and through the openings 28 into the spaces between the layers of insulation and displaces warm air contained therein upwardly and finally through the openings 23 and 24 into the food space II. In space II, the warm air comes in contact with the evaporator I2 and moisture contained therein is condensed on the evaporator. Consequently there is a continuous thermal circulation of cold dry air from the food space II into and through the spaces formed between shells I4 and I by the insulating layer IT. This assures that warm moist air does not remain in these spaces, where it would be cooled and its moisture condensed. Ii}, particularly when the refrigerator is first started, the cooling of the air in these spaces does result in some condensation,

. the liquid thus formed will be evaporated and removed from the insulation by the circulating air.

The cold air descending from the neighborhood of evaporator I2 causes that portion of inner shell I5 which lies directly beneath the evaporator to be cooled to a temperature lower than other parts of the shell. Consequently, the greatest tendency for condensation within the insulation occurs in that portion of the insulation adjacent to said portion of the shell I5. However, the air in this space, admitted thereto through openings I9, previously has been chilled to a still lower temperature by the evaporator I2 and its moisture content lowered to such an extent that no condensation can take place in even this coldest part of tion to take place upon changes in atmospheric pressure, or upon changes in pressure resulting from temperature changes. Thus air flowing in from the outside on account of these pressure variations can enter the insulation only after having been dried by passing through space I I.

In the embodiment shown in Figs. 3 through 5, the inner shell I5 as well as shell I4 is formed as air-tight as possible. Consequently no circulation of air may take place between the food space I I and the spaces between the shells I4 and I5. A condenser member 28 is disposed in heat exchange relationship with evaporator I2 and includes a conduit connected at difierent levels with the space 29 between the shell I5 and the innermost insulating layer I'I. As shown, condenser 28 includes a series of parallel conduits 30 connected together at their upper ends by means of a header 3| and at their lower ends by means of an inclined header 32. A conduit 33 connects header 3I with the upper part of space 29 while a conduit 34 connects header 32 with space 29 at a lower level. Conduits 30 are preferably disposed'between ribs 35 formed on evaporator I2 in order to assure a good heat transfer between the evaporator and the conduits. Header 32 at its lower end is formed with an opening 36 which i pregnated with such material.

is arranged to discharge above a drip pan 3! located below evaporator I2.

The operation of this embodiment is similar to that described in connection with Figs. 1 and 2, except that the drying of the air in the insulation is produced by the condenser 28. Air contained within the conduits 30 of the condenser is cooled and moisture condensed therefrom. This moisture may drain through opening 36 into the drip pan 31. The air thus cooled passes from the condenser to conduit 34 and downwardly through the space 29 in the direction indicated by the arrow 38. From space. 29 this air passes through the openings 20 formed within insulating layer I1 and causes warmer air contained between the layers to be displaced upwardly in the direction of the arrows 39 and to pass through the openings 23 formed in the insulating layers at their uppermost portions. This warm air, or a portion of it, is admitted to condenser 28 through conduit 33, where it is cooled and moisture condensed therefrom. Thus, in this embodiment, thermal circulation of air is maintained through the spaces in the insulation which assures that warm air will be displaced and cooled to reduce its moisture content.

,The embodiments shown in Figs. 6 and '7 differ from that shown in Figs. 3 through 5 only in the construction of the condenser. As shown in Figs. 6 and '7 the condenser 28 includes a flattened tubular member 48 which is secured in heat exchange relationship with the evaporator I2 by means of a sheet metal member 4| preferably welded to tubular member 40 and bolted to the evaporator. Tubular member 48 is connected to the space 29 by means of conduits 42 and 43 which correspond to conduits 33 and 34, respectively, in the previous embodiment.

The embodiment shown in Figs. 8 through 11 difiers from that shown in Figs. 3 through 5 in the nature of the insulating material. Instead of employing a plurality of layers II of insulation of the nature described in connection with the previous embodiments, a cork insulation 45 is employed. This insulation includes sheets of cork 46 suitably secured together to form a box-like structure. The cork sheets may be provided with a protective coating, such as asphalt or paraffin, or they may be wrapped in paper im- Laths 41 are secured to the inside and outside of the box-like structure to assure the provision of spaces 48 and 49 between the insulation and the shells I4 and I5, respectively. A sheet metal shell 58 is preferably disposed in the space 48 in order to prevent as far as possible the entrance of warm atmospheric air into the insulation. Insulation 45 is provided with an opening 5| in its lower part connecting spaces 48 land 49 and with a similar opening 52 in its upper part. A condenser 28 is connected to space 49 in the same manner as described in connection with Figs. 3 through 5.

Air contained within the insulation is cooled in condenser 28 and moisture condensed therefrom. The circulation of air through the condenser is maintainedby the force created by the difierence in specific gravity of the cooler air in condenser and the warmer air in the space 49. Through and between spaces 49 and 48 a thermal circulation of air also takes place. The air in space 49 being cooler than that in space 48, all the air in the insulation by thermal circulation thus is brought into contact with the cool surface of the condenser 28 and deprived of water.

The embodiment shown in Fig. 12 employs a heat insulation 60 which comprises a hermetically sealed double-walled shell 6|, within. which a partial vacuum exists, the walls of which are supported from collapse by means of granular material 62. Inner shell I5 is formed with a lower opening 63 which establishes communication between food space H and the space 64 formed between inner shell l5 and insulation 60. An opening 65 in the upper part of shell 15 serves the same purpose at the top. The operation oi this device is similar to that described in connection with Figs. 1 and 2.- Air cooled by contact with evaporator l2 passes downwardly through food space H and through opening 63 and displaces warm air upwardly through space- 64, from which it escapes through opening 65 to within food space i I, where it is chilled by the evaporator l2. Admission of warm atmospheric air, which. may leak through outer shell H, to space 66, is prevented as far as possible by means a seal 66 between insulation 60 and the frame i It will thus be seen that in all embodiments thermal circulation of air through the insulation is maintained for the purpose of removing therefrom warm moist air. Such air is passed in contact with either the evaporator of the refrigerating unit, or a condenser cooled thereby, in order that the moisture content of the air may be reduced to such an extent that condensation within the insulation is prevented. Also, it will benoted, that communication between the interior of the insulation and the atmosphere is prevented, insofar as this is practicably possible.

While I have shown and described several embodiments of my invention it is to be understood that this has been done for purposes of illustration only and that my invention is to be limited only by the appended claims viewed in the light of the prior art.

What is claimed is: 1. In a refrigerator cabinet, an inner shell open on a vertical side and having top, bottom and side walls and forming a food storage compartment, insulation outside of and spaced from said top, bottom and side walls and constructed and arranged to provide communicating vertical and horizontal interspaces, means to substantially seal the insulation exteriorly against inflow of air, air chilling means for cooling said food compartment, said inner shell and said insulation being apertured for circulation of air in a closed path including said food compartment and both horizontal and vertical interspaces, the horizontal and vertical inner spaces being so related that flow in horizontal interspaces is induced by flow in vertical spaces.

2. Structure as set forth in claim 1 in which the air chilling means is an evaporator disposed within the inner shell and the food compartment part of the closed path includes a conduit in heat transfer relation with said chilling means and communicating with the apertures in said inner shell.

3. In a refrigerator cabinet, an inner shell open on a vertical side and having top, bottom and side walls and forming a food storage compartment, one or more self-sustaining boxlike cardboard members-surfaced with aluminum foil and I CARL (mom Moms. 

